The purpose of this study is to correlate the structural properties of the tissues of the spine with the material properties and geometrical distribution of the tissues of which these elements are composed and with age and state of degeneration. In particular viscoelastic and rate dependent properties will be measured. Creep, relaxation, cyclic loading and programmed variable rate tests will be performed in tension, bending, torsion, compression and combined loading. The deformation of various key tissues, i.e., spinal cord, nerve roots and discs during structural tests of intact spinal segments obtained at autopsy will be determined. Serial sections will be studied with a Scanning Electron Microscope to determine the type and extent of lesions, microcracks, and tissue degeneration occuring naturally and after loading. A closed loop, programmable, hydraulic testing facility will be used to apply loads to the specimens at precisely controlled rates, frequencies and amplitudes. Deformations will be determined using a variety of methods including a television microscope observation system and roentgenographic analysis. The long-range goal of this research is to provide currently unavailable information regarding structural and viscoelastic properties of the tissues of the spine to provide a quantitative framework for the development of mechanisms of lower back disorders and pain.